1. Field of the Invention
The present invention relates to a light attenuation device applied to regular eyeglasses or clip on eyeglass lenses used as a vision aid during night driving.
2. Description of the Prior Art
Driving automobiles at night is a much more difficult task than during daylight due to the limited illumination provided by the headlights of the automobile. Visual detection of objects becomes more difficult as the distance from the automobile increases due to the lowering intensity of the reflected light from the object as the distance from the headlight increases. Vision is further inhibited when oncoming automobile headlights or light from following automobiles shines into the eyes of the driver, causing a reduction in pupil size and resultant loss of sensitivity of vision. The ability of the driver to detect objects in the path of his travel diminishes greatly as the intensity of the light from the oncoming or following automobile's headlight increases. Furthermore, the ability to regain full vision after an oncoming automobile passes is delayed as the pupil expands back open to regain full sensitivity to the comparatively weak reflected light from the headlights. As the age of the driver increases, the sensitivity of the eyes to weak light diminishes, and the recovery period as the pupil opens back up after an oncoming automobile has passed increases also, making night time driving for middle aged and older drivers even more difficult.
At present there are few night driving glasses on the market and they use tinting of the eyeglass lenses over the full surface of the lens, or in a band, which travels the full width of the eyeglass lens. While these lens configurations can reduce the intensity of the light received by the driver's eyes, they also reduce the intensity of the light reflected back to the driver from the objects illuminated by the driver's automobile headlights for much of the visual field outside the area of the oncoming headlights. Thus, little or no net gain in vision is obtained during the period in which the driver is subjected to oncoming or following automobile lights. Moreover, many standard eyeglasses incorporate antireflection coatings, which do reduce glare and help retain visual contrast in the presence of high intensity light. These eyeglasses may be used in conjunction with application of the described light attenuation device to provide added benefits of glare reduction through antireflection coatings.